Increase in use of sophisticated car stereos in recent years has caused increase in the theft of the stereos. In order to prevent the theft of the stereo, there has been proposed measures for the stereos. In accordance with the one of the measures, a grille having a plurality of push button for a stereo is provided to be separated from the body of the stereo, and is detachably attached to the front portion of the stereo.
FIG. 4 shows the above described prior art. The car stereo 1 comprises a car stereo body 4 and a detachable grille 2 attached to the body 4. The body 4 has recessed panel 3 mounted at the front thereof. The panel 3 has a cassette opening 5 having a lid 6. A series of terminals 9 which are connected to terminals (not shown) provided at the back of the grille 2 when the grille is attached, are formed on the panel 3. The grille 2 has a cassette opening 7 which coincides with the cassette opening 5 of the body 4 and various operation keys 8.
In operation, a cassette tape is inserted into the car stereo body 4 through the cassette openings 7 and 5. A loading mechanisms provided in the body 4 is operated to carry the cassette to a playback position where the cassette is played.
In order to detach the grille 2 from the panel 3, the grille 2 is depressed at one side. A push-push mechanism (not shown) provided in the body 4 is operated to project the grille 2. The grille 2 is then pulled off the panel 3 of the body 4.
When the grille 2 is taken out, the stereo body loses the appearance as a car stereo. Hence, if the driver takes the grille 2 with him when leaving the vehicle, the theft of the car stereo is prevented.
When the grille 2 is attached on the panel 3 of the car stereo body 4, the terminals on the back of the grille 2 is connected to the terminals 9 of the body 4. A control unit provided in the car stereo body 4 detects that the grille 2 is attached when predetermined corresponding pairs of terminals of the grille 2 and the body 4 are connected with one another. The control unit is then operated to supply power to the terminals of the grille 2 from a battery provided in the body 4.
However, for convenience of manufacturing various stereos, it is required that the same parts may be used in common in various types of car stereo. As a result, the dimensions of grilles of various types are determined at the same value. Thus, a grille can be fit in a car stereo body which do not correspond to the grille. If a grille is erroneously attached to an unsuitable car stereo body, current inappropriately flows in electronic equipment in the car stereo body and the grille, which possibly damages them. In some case, since the terminals are arranged differently in each type of the grille, the car stereo may be erroneously operated because of erroneous connection of the terminals.